A structure disclosed in Patent Document 1 is known as a vehicle door opening-closing control device which controls an opening-closing operation of a vehicle door by using an infrared sensor. In this conventional example, a foot detection sensor which outputs a signal of infrared rays and the like toward the ground is mounted on a vehicle. After authentication of a portable wireless terminal held by a user, an opening-closing operation of the door takes place when the driven foot detection sensor detects the user.
Meanwhile, in the above-described conventional example, determination of the foot is performed by comparing an amount of light reflection from the foot with a prescribed detection threshold. However, the vehicle is stopped at various locations with different optical environments and brightness and other factors of a detection region set outside of the vehicle may vary depending on the stopped location. The conventional example therefore has a problem of an increase or decrease in the amount of light reflection from the foot and significant deterioration in detection reliability as a consequence.
In the meantime, as shown in Patent Document 2, moving average values of multiple pieces of data on the amounts of light reflection are often compared with a prescribed detection threshold to improve the detection accuracy. In this case, however, this configuration can only reduce or eliminate an influence of noise on an observation value, but cannot prevent deterioration in detection accuracy due to a change in the detection environment.